Thanks guys. Top is going to be thick, around 5” so yeah, most of the festool clamps wont work. I might use some sacrificial material so i dont mark the top if i do decide to cross cut on there.
I was mainly looking at using bench dogs and some other hold downs. Are the iron hold downs available in a 20mm option?
I might build in a moxon vise on one end so two rows of holes using that vise would be good. I just like using the MFT and not having to worry about where the workpiece is, as theres always a spot for a clamp/hold-down.
Those popup dogs are great little gadgets. But i think i want the holes over that style.
I just priced up the material cost for the top….. yikes 😳
As a predominantly (serious) handtool woodworker for a few decades, who considers the bench to be the main tool in my workshop, I would advise:
1. 3/4" dog holes for hand tool-orientated hold downs from Gramercy and Veritas. The 20mm Festool stuff needs its own bench. Stick to the traditional methods - they have been around for centuries for a good reason.
2. Combine other traditional holding tools, such as a face vise (I use a leg vise) and tail vise (my preference is the Benchcrafted wagon vise). There are a number of simple fixtures, such as a Doe's Foot, Sticking Board, and shooting board, all of which I do not like without.
3. Do not - repeat not - build a Moxon vise into the bench front. This immediately nullifies the reason for a Moxon, which is to lift the work piece up to a comfortable height. A "Moxon" built into a bench is simply a double screw vise.
4. A 5" thick bench will come back and bite you. It is too thick for hold downs from Gramercy (unless you back recess the mortice below the bench). These (and other) hold downs do best with 3-4" thick benches. My bench is 3 1/2" thick European Oak (on a hefty Jarrah base).
5. Round bench dogs are less desirable than square bench dogs. The latter are more directional, which is better. Round dogs are easier to create, and can be done later. Square dog holes must be planned in advance. I make use of both types, as the round ones (from Veritas) have a place, but along the bench front they are square.

If you are interested, I can provide more details of the set up I have found helpful.
Regards from Perth
Derek