When putting braid on a baitcast reel do you guys use mono or tape as backing?

Tape.

Mono but ^^^Tape sounds easier.

I use mono

I use braid to back braid

mono with tape over the knot. Line is lighter than tape and the single price of tape will keep your line from getting snagged on the knot midcast.

Exactly what I do

What does weight of line versus tape have to do with backing?

Most people use mono for backing with braid. Reels are designed to be fully spooled (or almost) for best performance. Because braid is smaller diameter and much more expensive than mono, it takes a lot more line and $ to fill a reel to capacity with braid. In this regard, I understand why folks use it as backing for braid. Plus, if tied properly, mono will not slip on your spool and braid will.

I think that most folks who fish braid use it for specialized applications like pitching in heavy cover, etc. Full spools aren't needed in these presentations.

Myself, when fishing for BIG fish, I want my spool full of braid to allow for multiple reties during the day. This is why I only use tape for my backing. Keeps the line from slipping on the spool. All the other talk about "cushioning" is just that.

because the line is lighter than the tape thus making the tape much smoother and sort of lubricates the line so the knot stays consistent with the braid while casting.

Mostly a preference thing, not to mention more economical to have mono 1/4-1/2 spooled, then braid on top.

it's best to splice braid to mono to braid to mono to braid to mono over and over again in 12" sections until the spool is full. This way you have a choice between using mono or braid, but always of course start out with mono as your backing ....... and a piece of tape at each knot. Oh and a Tatula is best for this application .... no micro guides!

tape

I don't use a backing. When the braid seems to be getting worn, I unspool it, and re-spool it from the unused end.

this

Tape