It looks quite neat and of good quality.
Personally I run a non-return valve after each pump but before they join via a "Y" piece. Non-return valves ensure one pump won't fight against the other if pressures are mismatched. The "converter block" on the unit you link too will offer a degree of restriction also due to the sharp change of direction the fuel goes through leaving each pump. I would prefer a "Y" adapter.
Overall, it will do the job I'm sure, just that there is technically a better way of doing it. Just my opinion, of course.