We converted our typed letter into both yellow letters and postcards so expect a ton of both.  

and was the basic message of the oversize postcard?

If you use a HELOC, I would think about a BRRRR-ish strategy (No perfect BRRRR exists right now unless you go full off-market door knocking/postcard campaign/etc) to where you can refinance and get some of that money back, so you don't have $25k chunks of money at a 9-10% interest rate floating out there indefinitely.

At least I can throw away the hundreds of postcards and letters which doesn't waste as much of my time.   

We like postcards - they have higher visual impact and cost about 1/2 what letters cost, meaning we can hit twice as many people for the same marketing $.  

I'm MUCH more likely to look at a postcard than an unsealed letter.

When Wholesaling, you would want your team to focus on marketing (yellow letters, post cards, etc), negotiation/acquisition, and another person to focus on building a buyer's list to unload the wholesale properties.

Be the one that keeps mailing longer than others do.And something I may start...and you might want to try, spread your letters out farther with a post card in between, that IS the same every time.  

It's 17.5 cents postage per postcard (over-sized postcards...

If you're doing a postcard, it probably doesn't matter.