Hello Scotty,
It look to be as if maybe you've been wearing and enjoying those new Penny shoes for only a few days and you're already thirsting for a bigger slice of the action! It always happens!
I have successfully increased the height of MANY of my pairs of high heels over the years, but there are things to be careful about
:
Firstly, the balance of the shoe can be ruined if the increase is too great. Put your shoe on the table and look at it from the side. Shoes are made with a 'toe-spring' whereby the sole under the ball of the foot is resting on the table, but the toe-part of the sole is maybe 1/2" off the table. Experiment by putting something (like playing cards or a thin book) under the heel to raise its height. This will tilt the shoe forward, but you must stop increasing the heel height when the toe-box's sole is flat on the table.
Any further increase in heel-height would lift the ball of the foot into the air! Measure the distance between the base of the heel and the table, and that is the maximum extent to which you can increase the heel (usually something between 1/4" and 3/4").
Secondly it seems unnecessary to by a whole new pair of shoes just to aquire a bit of heel. Instead, carefully lever-off the rubber heel-soles of your existing shoes with a screwdriver of chisel. Then, with a strong contact adhesive like Evostik, glue-and-pin on to the the base of the sole-less heel a plate of hard wood of the thickness of your chosen heel increase, and slightly larger than the heel-base. Then rasp (file) down the protruding wooden edge to follow the exact shape and profile of the high heel. Then cover the visible sides of both heels (old leather, wood and all) with very thin new leather, again using Evostick, the joint in the leather coming under the hidden front-face of the heel. If the leather is thin enough, turn 1/2" in under the base of the heel before re-gluing and pinning the heel-soles back on to the new increased-height heels. If the leather is not thin enough to do this, simply trim it off where it will meet the heel-sole.
Thirdly, it occurs to me that if you have the money for another pair of shoes, you might as well be some shoes that already have a slightly higher heel to save yourself all that work. I suggest "Vivian" from Womenshoes:
http://womenshoesplus.com/Detail_Page/Vivian.html
I've had more than one pair of these and they're great for guys' discreet street-heeling. The heel is advertised as 2 1/2", but as the whole shoe getsd proportionally bigger in the larger sizes, mine came through as just over 3".
Happy Heeling Scotty!
Cheerfully yours, Heelfan